Modern vehicles may attempt to sense whether an occupant is located in a vehicle seat. However, present sensing systems can be inaccurate. For example, camera systems may have difficulty detecting the presence of an occupant—e.g., particularly when the occupant is wearing apparel around the head or face (e.g., hats, hoodies, etc.). Position sensors in or around the vehicle seat may attempt to determine whether the seat is occupied based on seat belt usage information; however, these systems can be inaccurate because they do not account for slack in the seatbelt.